U.S. patent number 9,297,967 [Application Number 13/640,392] was granted by the patent office on 2016-03-29 for device for converting signal.
This patent grant is currently assigned to Hewlett Packard Enterprise Development LP. The grantee listed for this patent is Sagi Varghese Mathai, Paul Kessler Rosenberg, Joseph Straznicky, Michael Renne Ty Tan. Invention is credited to Sagi Varghese Mathai, Paul Kessler Rosenberg, Joseph Straznicky, Michael Renne Ty Tan.
United States Patent |
9,297,967 |
Rosenberg , et al. |
March 29, 2016 |
Device for converting signal
Abstract
A device for converting and optionally processing an optical
signal comprises an optical cable having an optical-electrical
conversion device at one end, the optical-electrical conversion
device to convert the optical signal to an electrical signal or an
electrical signal into an optical signal; a electrical package to
removably receive the optical-electrical conversion device and
generate processed signal; and a general circuit board attached to
the electrical package and operable to receive the processed
signal.
Inventors: |
Rosenberg; Paul Kessler
(Sunnyvale, CA), Mathai; Sagi Varghese (Palo Alto, CA),
Ty Tan; Michael Renne (Menlo Park, CA), Straznicky;
Joseph (Santa Rosa, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Rosenberg; Paul Kessler
Mathai; Sagi Varghese
Ty Tan; Michael Renne
Straznicky; Joseph |
Sunnyvale
Palo Alto
Menlo Park
Santa Rosa |
CA
CA
CA
CA |
US
US
US
US |
|
|
Assignee: |
Hewlett Packard Enterprise
Development LP (Houston, TX)
|
Family
ID: |
44861850 |
Appl.
No.: |
13/640,392 |
Filed: |
April 30, 2010 |
PCT
Filed: |
April 30, 2010 |
PCT No.: |
PCT/US2010/033310 |
371(c)(1),(2),(4) Date: |
October 10, 2012 |
PCT
Pub. No.: |
WO2011/136818 |
PCT
Pub. Date: |
November 03, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130071064 A1 |
Mar 21, 2013 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N
5/225 (20130101); G02B 6/4292 (20130101); H05K
3/30 (20130101); G02B 6/42 (20130101); Y10T
29/4913 (20150115) |
Current International
Class: |
G02B
6/30 (20060101); G02B 6/42 (20060101); H04N
5/225 (20060101); H05K 3/30 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2005317658 |
|
Nov 2005 |
|
JP |
|
2007093731 |
|
Apr 2007 |
|
JP |
|
10-20070111303 |
|
Nov 2007 |
|
KR |
|
220388 |
|
Feb 1994 |
|
TW |
|
200942885 |
|
Oct 2009 |
|
TW |
|
Other References
PCT Search Report, Dec. 29, 2010, HPDC, PCT Application No.
PCT/US2010/033310, Filed Apr. 30, 2010. cited by applicant.
|
Primary Examiner: Wong; Tina
Attorney, Agent or Firm: Thorpe North & Western
Claims
What is claimed is:
1. A device for converting signal, comprising: an optical cable
having an optical-electrical conversion device comprising an active
optical element attached to an optical interface at one end, the
optical-electrical conversion device for converting optical signals
from the optical cable to electrical signals or for converting
electrical signals to optical signals to the optical cable; an
electrical package to: receive the optical cable having the
optical-electrical conversion device in a manner that the optical
cable having the optical-electrical conversion device is removable
from the electrical package; receive an electrical signal from the
optical cable; generate processed signals from the electrical
signal; and a general circuit board attached to the electrical
package for receiving the processed signal, wherein the optical
interface comprises: electrical contacts to provide electrical
communication between the electrical package and the
optical-electrical conversion device; and at least one lens to
provide optical communication between active optical element and
the optical cable.
2. The device of claim 1, wherein the active optical element
comprises photo detectors or lasers.
3. The device of claim 2, wherein the active optical element
includes photodetectors, and the photo detectors are selected from
the group consisting of optical detectors, chemical detectors,
photoresistors, photovoltaic cells, photodiodes, phototransistors,
light emitting diodes, and combinations thereof.
4. The device of claim 1, wherein the optical-electrical conversion
device includes at least one alignment structure for aligning one
or more optical waveguide from an optical cable to an active
optical element of the optical-electrical conversion device, the at
least one alignment structure protrudes from the optical-electrical
conversion device.
5. The device of claim 1, wherein the optical interface is attached
to the active optical element and comprises electrical attachment
pads and traces in electric communication with the active optical
element, the electrical attachment pads and traces operable to mate
with corresponding electrical contacts on the electrical
package.
6. The device of claim 1, wherein the optical cable comprises a
fastening feature for an additional point of attachment of the
optical cable to the electrical package.
7. The device of claim 6, wherein the fastening feature is a
clip.
8. A method of manufacturing the device of claim 1, comprising:
attaching the electrical package to the general circuit board; and
connecting the optical cable to the electrical package by mating
the optical-electrical conversion device at one end of the optical
cable to the electrical package, wherein the optical-electrical
conversion device is operable to convert an optical signal into an
electrical signal or convert an electrical signal into an optical
signal.
9. A device for converting signal, comprising; an optical cable
including an optical waveguide; and an optical-electrical
conversion device attached at one end of the optical cable, the
optical-electrical conversion device for converting optical signal
to electrical signal or for converting electrical signal to optical
signal, said optical-electrical conversion device, including: an
active optical element, an optical interface positioned between the
optical waveguide and the active optical element, and which allows
optical communication between the optical waveguide and the active
optical element, and at least one alignment structure for optically
aligning the optical waveguide of the optical cable with the active
optical element, wherein the optical interface comprises an
electrical contact to allow electrical communication between the
active element and an electrical package, and wherein the
electrical package is to receive the optical-electrical conversion
device in such a manner that the optical conversion device is
removable from the electrical package.
10. The device of claim 9, wherein the optical cable comprises a
plurality of optical fibers, and the active optical element
includes a plurality of corresponding photodetectors, lasers, or
combinations thereof.
11. The device of claim 9, wherein the optical interface comprises
a lens positioned between an optical fiber of the optical waveguide
and a photodetector or laser of the active optical element.
12. A method for converting optical signal to electrical signal and
processing said electrical signal, comprising; receiving an optical
signal; converting the optical signal to an electrical signal
within an optical cable, said optical cable having an
optical-electrical conversion device comprising an active optical
element attached to an optical interface at one end, the
optical-electrical conversion device operable to convert optical
signal to electrical signal and to convert electrical signal to
optical signal, the active optical element receiving the optical
signal through at least one lens in the optical interface;
transferring the electrical signal from the optical cable to an
electrical package through an electrical contact in the optical
interface; generating a processed signal at the electrical package;
and transferring the processed signal from the electrical package
to a general circuit board attached to the electrical package,
wherein the optical-electrical conversion device is removable from
the electrical package.
13. The method of claim 12, further comprising the preliminary step
of removably attaching the optical cable to the electrical
package.
14. The method of claim 12, further comprising converting
electrical signal to optical signal for bi-directional
communication.
15. The device of claim 1 comprising: a standoff structure between
the optical-conversion device and the optical cable to support the
optical cable to the optical conversion device.
16. The device of claim 1 wherein the electrical package includes
at least one post extending from the general circuit board, the at
least one solder post to attach the electrical package to the
general circuit board.
17. The device of claim 1 wherein the electrical package includes a
recess to receive the active optical component.
18. The device of claim 1 wherein the electrical package includes
at least one processor and wherein the optical-electrical
conversion device is removable from the electrical package without
removal of the at least one processor.
19. The device of claim 9 wherein the optical cable includes a
fastening feature to attach the optical cable to the electrical
package.
Description
BACKGROUND
Generally, optical packages have an optical interface, where an
optical cable is attached to receive or transmit an optical signal.
Optical packaging generally co-locates integrated circuits and
active optical components. Therefore, a package is typically
designed to be used with an electrical socket, since delicate
optical components cannot withstand exposure to Printed Circuit
Board (PCB) solder reflow temperatures.
Optical packages can include optical cables having optical fibers.
Optical fibers are widely used in fiber-optic communications, which
permits transmission over longer distances and at higher bandwidths
(data rates) than other forms of communications. Fibers are used
instead of metal wires because signals travel along them with less
loss, and they are also resistant to electromagnetic interference.
Fibers are also used for illumination, and are wrapped in bundles
so they can be used to carry images, thus allowing viewing in tight
spaces. Specially designed fibers are used for a variety of other
applications, including sensors and fiber lasers.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional features and advantages of the disclosure will be
apparent from the detailed description which follows, taken in
conjunction with the accompanying drawings, which together
illustrate, by way of example, features of the disclosure; and,
wherein:
FIG. 1 is a perspective view of an optical-electrical conversion
device in accordance with an example of the present disclosure;
FIG. 2a is a perspective view of an optical cable in accordance
with an example of the present disclosure;
FIG. 2b is an end view of an optical wave guide in accordance with
an example of the present disclosure;
FIG. 3 is a perspective view of an electrical package attached to a
general circuit board in accordance with an example of the present
disclosure; and
FIG. 4 is perspective view of a device for converting and
processing an optical signal in accordance with an example of the
present disclosure.
DETAILED DESCRIPTION
Before the present disclosure is described, it is to be understood
that this disclosure is not limited to the particular process steps
and materials disclosed herein because such process steps and
materials may vary somewhat. It is also to be understood that the
terminology used herein is used for the purpose of describing
particular examples only. The terms are not intended to be limiting
because the scope of the present disclosure is intended to be
limited only by the appended claims and equivalents thereof.
It must be noted that, as used in this specification and the
appended claims, the singular forms "a," "an," and "the" include
plural referents unless the context clearly dictates otherwise.
As used herein, "optical-electrical conversion device" refers to an
optical interface attached to an active optical element. Generally,
the active optical element receives and converts an optical signal
into an electric signal.
As used herein, "optical cable" refers to a cable having optical
fibers or optical wave guides that transmits an optical signal on
to an active optical element through an optical interface.
As used herein, "optics" or "optical components" generally refer to
the optical interface and the active optical element(s).
As used herein, "electrical package" refers to a substrate having
at least one integrated circuit, or other processor, and an open
area for receiving an optical-electrical conversion device.
Generally, the electrical package is attached to or is otherwise in
electrical contact with, or in communication with, the general
circuit board. Additionally, the electrical package generally
processes an electrical signal from an optical cable.
As used herein, a plurality of items, structural elements,
compositional elements, and/or materials may be presented in a
common list for convenience. However, these lists should be
construed as though each member of the list is individually
identified as a separate and unique member. Thus, no individual
member of such list should be construed as a de facto equivalent of
any other member of the same list solely based on their
presentation in a common group without indications to the
contrary.
It has been recognized that it would be advantageous to develop
optical devices suitable for a wide variety of applications. In
accordance with this, devices and methods described herein can
include an optical device that encloses an optical-electrical
conversion device at one end of an optical cable for attachment to
an electrical package on a circuit board. As such, the present
disclosure provides optical devices allowing for varying optical
packages on circuit boards via a removable cable containing the
active optical elements rather than having such elements enclosed
or embedded on the circuit board and/or electrical package.
As such, a device for converting (e.g., optical signal to
electrical signal, or vice versa), and processing such signal, can
comprise an optical cable having an optical-electrical conversion
device at one end, the optical-electrical conversion device to
convert an optical signal to an electrical signal or to convert an
electrical signal to an optical signal; a electrical package to
removably receive the optical-electrical conversion device and
generate processed signal; and a circuit board attached to the
electrical package and operable to receive the processed
signal.
In another embodiment, a device for converting signal (e.g.,
optical signal to electrical signal, or vice versa) can comprise an
optical cable including an optical waveguide, and an
optical-electrical conversion device attached at one end of the
optical cable. The optical-electrical conversion device can be
configured for converting optical signal to electrical signal or
for converting electrical signal to optical signal. More
specifically, the optical-electrical conversion device can include
an active optical element, an optical interface positioned between
the optical waveguide and the active optical element, and an
alignment structure. The optical interface allows optical
communication between the optical waveguide and the active optical
element. Also, the alignment structure is positioned for optically
aligning the optical waveguide of the optical cable with the active
optical element.
It is noted that when describing an optical device or a method of
manufacturing or using such a device, each of these descriptions
can be considered applicable to each of these examples, whether or
not they are explicitly discussed in the context of that example.
For example, in discussing active optical elements for the optical
device, those active optical elements can also be used in a method
for manufacturing such a device, and vice versa.
Various modifications and combinations that can be derived from the
present disclosure and illustrations, and as such, the following
figures should not be considered limiting.
Turning now to FIG. 1, an optical-electrical conversion device 100
can comprise an optical interface 102 attached to an active optical
element 104. Attachment of the active optical element to the
optical interface can be by any method known in the art. For
example, the optical interface can be metalized to allow attachment
of the active optical element by flip chip attachment.
Additionally, other known methods of attachment include, without
limitation, adhesive followed by wire bonding, direct chip
attachment, bonders, polymer adhesives, epoxy bonding, soldering,
etc. In one example, an "underfill," which is a thin adhesive layer
that is applied between a flip chip die and the substrate it is
attached to, can be used as a coating adhesive to improve the
robustness of the chip attachment. Generally, the adhesive `fills
under` the gap between the two attached elements and strengthens
the attachment. Notably, in one example, the underfill can be
optically transparent at wavelengths of interest allowing light to
pass through it. Additionally, a "glob top" can be used as a
coating adhesive to improve the robustness of the chip attachment.
Generally, a glob top is an adhesive coating typically applied over
exposed wire bonded integrated circuits (ICs) to protect the
delicate wires and chips. Glob top can be typically used when ICs
are attached directly to large printed circuit boards (PCBs)
(process known as `Chip On Board` (COB), rather than the IC
packaged separately in a plastic or ceramic package.
The optical interface 102 generally includes electrical attachment
pads and traces 106 and alignment structures 108. Additionally, the
optical interface can include standoffs 110 and/or a lens(es) 112.
Generally, lenses can be positioned over photodetectors 114 or
lasers 116 to focus the transmitted optical signals, respectively,
into or out of an optical waveguide, e.g., a plurality of optical
fibers. Generally, the lens(es) may or may not be present in the
optical interface. In one example, where a laser transmits into a
multimode fiber, the lenses may be absent. In another example where
a photodiode has a small active area, e.g., 50 .mu.m diameter for
example, a lens may be used. As discussed herein, the
optical-electrical conversion device can comprise lasers that emit
an optical signal. As such, the optical cables described herein can
allow for optical communication between a processor and a secondary
device.
Continuing with FIG. 1, and with some reference to FIG. 2a, the
alignment structure 108 can be used to position the
optical-electrical conversion device with respect to the optical
cable 200. In one example, the positioning can be a somewhat to
very precise alignment. Additionally, the optical interface
metallization features, e.g., electrical traces, can determine the
position of the optical active elements by being located with
respect to alignment structures on the top side of the optical
interface. The alignment structure can be mated with alignment
holes 202 providing for positioning of the active optical element
with respect to the optical fibers 208 within the optical waveguide
204 (shown in FIG. 2a and discussed in further detail below). As
mentioned, in one example, the positioning can be a precise
alignment. The present examples can provide optical alignment
precision for both 1) multimode alignment, with a radial
positioning accuracy of less than 5 microns and/or 2) single mode
alignment with a radial positioning accuracy of less than 1
micron.
The optical interface 102 can be manufactured from any materials
that are generally used for optical interface manufacture,
including without limitation, glass, sapphire, silicone, plastics,
high temperature plastic, ceramics, etc. In one example, the
material can be glass and/or sapphire. In another example, the
optical interface can be a transparent substrate. As mentioned, the
active optical element 104 can comprise photodetectors 114 or
lasers 116. In one example, the active optical element can contain
an array of photodetectors. In another example, the active optical
element can contain an array of lasers. In another example, the
photodetectors can be selected from the group consisting of optical
detectors, chemical detectors, photoresistors, photovoltaic cells,
photodiodes, phototransistors, light emitting diodes, and
combinations thereof. The lasers can be selected from the group of
vertical cavity surface emitting lasers, fabry-perot lasers,
distributed feedback lasers, etc.
Turning now to FIGS. 2a and 2b, an optical cable 200 can comprise
channels 202 for receiving the alignment structures 108 from the
optical-electrical conversion device 100. Additionally, the optical
cable can comprise an optical waveguide 204, which generally
includes optical fibers 208 (shown as an end view in FIG. 2b). As
previously described, the active optical elements 104 can be more
precisely aligned with the optical fibers in the optical waveguide
by more precise attachment of the active optical elements to the
optical interface 102 via flip chip attachment, or other means, and
further use of the alignment structures to mate with the channels
of the optical cable. In one example, the optical cable can
comprise a fastening feature 206, such as a clip, fitting, or the
like.
The devices described herein can provide precise alignment of
optical components with cables and to other devices. In one
example, the active optical element 104 can be attached to an
optical cable 200, as described herein, so that the active
components of active optical element, which can include lasers 116,
photodetectors 114, etc., can either transmit light into the optic
waveguide or receive light from the optic waveguide. In another
example, the optical cable can contain an optical waveguide 204
having a plurality of optical fibers 208 that are positioned with
respect to channels 202 on the face of the cable connector. As
such, when the active optical element is attached to the optical
cable, the alignment structures of can be positioned into the
channels. Thus, the active components, e.g., laser or
photodetectors, can be precisely positioned with respect to the
optical fibers.
It is noted that while the present figures have shown certain
features of the present disclosure, such features are merely
exemplary and do not limit the disclosure as set forth herein. For
example, while FIG. 2 shows a clip 206a as a fastening feature 206,
such disclosure is not limiting as the present disclosure
contemplates the use of any type of fastening feature, e.g.,
fittings, screws, etc. Additionally, while the fastening feature is
depicted as a separate component from the optical cable; i.e., it
is removable from the optical cable housing, the present disclosure
contemplates the use of a single molded assembly; i.e., where the
fastening feature is single molded with the optical cable
housing.
The optical cables described herein can have the active optical
elements incorporated therein allowing for removal of the optical
components from the electrical package. Such removability provides
benefits not found with traditional optical components that are
attached to an electrical package, or processor, during
fabrication. Generally traditional optical components are
permanently attached to a processor. The present optical cable
allows for increased optical functionality as the optics can be
switched out by removing of the optical cable rather than removal
of the optical cable and the processor, and lower costs as the
optics can be manufactured separately from the processor and can be
attached subsequent to the processor manufacturing. Additionally,
the optics described herein can be located at the end of the
optical cable rather than buried inside the optical cable allowing
for heat dissipation.
Turning now to FIG. 3 (and referring back to FIGS. 1 and 2), an
electrical package 302 attached to a general circuit board 304 (a
portion of which is shown). The electrical package can comprise
integrated circuits 306. The electrical package can also comprise
attachment features 308 for attachment of the electrical package to
the general circuit board. In one example, the attachment features
can be solder posts 308a. Additionally, the attachment features can
be snap in clips, screws, or other metal posts. The electrical
package 302 can also contain elements such as solder spheres,
electrical pins, etc. for making electrical contact to the
electrical circuit board 304. The solder posts can be any shape. In
one example, the solder posts can be solder spheres. The electrical
package can be a modified plastic ball grid array. Electrical
connection between 302 and the system PCB can be made removably by
means of a socket as well as by permanent attachment with solder.
The electrical package can also include an open area 310 for
receiving the optical-electrical conversion device 100 at the end
of the optic cable 200. Additionally, a recessed area 312 can be
fabricated into the electrical package by molding, milling or other
means to receive the active optical element 104 attached to the
optical interface 102 of the optical-electrical conversion device
100. This recessed area can provide clearance for the active
optical element when the optical cable is mated to the electrical
package.
As previously discussed, the optical cable 200 can comprise a
fastening feature 206 for an additional point of attachment of the
optical cable to the electrical package 302. The electrical package
can have slots 314 operable to receive the fastening feature. As
previously discussed, the optical interface can be attached to the
active optical element and comprises electrical attachment pads and
traces 106 in electric communication with the active optical
element. Additionally, the electrical traces can mate with
corresponding electrical contacts 316 on the electrical package. In
one example, the electrical package can comprise at least one
integrated circuit and electrical contacts that mate with
electrical traces from the optical cable. Additionally, the
electrical contacts can be in electrical communication to the
portions of the integrated circuits that can either drive the
lasers or receive and amplify signals from the photodetectors.
Further, the electrical contacts can supply power and grounding to
the optical cable.
Turning now to FIG. 4, a schematic showing the various parts
previously described as they are assembled together is shown. Thus,
both the device and method for manufacturing the device is
illustrated by example therein. Specifically, the method of
manufacture can comprise attaching an electrical package 302 to a
general circuit board 304. Additional steps include connecting an
optical cable 200 to the electrical package by mating the
optical-electrical conversion device 100 at one end of the optical
cable to the electrical package. The optical-electrical conversion
device can convert an optical signal into an electrical signal. In
another example, the optical-electrical conversion device can
convert an electrical signal into an optical signal. The method can
further comprise aligning optical fibers from an optical waveguide
to an optical active element of an optical-electrical conversion
device via alignment structures. Additionally, the method can
include attaching the electrical package to the general circuit
board by soldering the electrical package to the general circuit
board using a plurality of soldering posts and/or balls.
It is understood that the optical cable 200 may transfer a
mechanical load to the electrical package 302. As such, the present
disclosure provides solder posts 308a, attachment features 308, or
other mechanical stress relief to the device. The solder posts can
be soldered into the general circuit board during a standard reflow
process. Other techniques may be employed to protect the electrical
contacts and electrical package 302 in general from mechanical
loading through the optical cable, such as the use of plastic or
sheet metal clips that snap onto the general circuit board and/or
electrical package. The optical cable may also be designed to
release from the electrical package if the physical load exceeds a
set value. In one example, magnetic attachment can perform this
function.
In another example, a method of manufacturing the device described
herein can comprise attaching the electrical package to the general
circuit board and connecting the optical cable to the electrical
package by mating the optical-electrical conversion device at one
end of the optical cable to the electrical package. Further, the
optical-electrical conversion device can convert an optical signal
into an electrical signal or an electrical signal into an optical
signal.
In another example, a method for converting optical signal to
electrical signal and processing the electrical signal accordingly
is provided. The method includes generating an optical signal and
converting the optical signal to an electrical signal within an
optical cable. The optical cable can have an optical-electrical
conversion device at one end, and is operable to convert optical
signal to electrical signal and to convert electrical signal to
optical signal. Additional steps include transferring the
electrical signal from the optical cable to an electrical package,
generating a processed signal at the electrical package, and
transferring the processed signal from the electrical package to a
general circuit board attached to the electrical package. In one
particular example, the method can comprise the preliminary step of
removably attaching the optical cable to the electrical package, as
described herein. The method can further comprise converting
electrical signal to optical signal for bi-directional
communication.
In summary, the present disclosure provides a removable optical
cable having the active optical components attached thereto such
that the optic can be easily removed from the general circuit
board. It is noted that these methods and devices can be modified
independently of each other. Additionally, it is notable that the
general circuit board and/or electrical package can be manufactured
via standard solder reflow processes as the optics are contained
wholly within the optical cable, which can be subsequently attached
the general circuit board and/or electrical package. Further, the
present devices and methods can provide for increased functionality
as the optics can be easily replaced by removal of the optical
cable while reusing the electrical package.
While the disclosure has been described with reference to certain
examples, those skilled in the art will appreciate that various
modifications, changes, omissions, and substitutions can be made
without departing from the spirit of the disclosure. It is
intended, therefore, that the disclosure be limited only by the
scope of the following claims.
* * * * *